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// SPDX-License-Identifier: GPL-2.0
/*
* Driver for Elan touchscreens that use the i2c-hid protocol.
*
* Copyright 2020 Google LLC
*/
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/pm.h>
#include <linux/regulator/consumer.h>
#include "i2c-hid.h"
struct elan_i2c_hid_chip_data {
unsigned int post_gpio_reset_on_delay_ms;
unsigned int post_gpio_reset_off_delay_ms;
unsigned int post_power_delay_ms;
u16 hid_descriptor_address;
const char *main_supply_name;
};
struct i2c_hid_of_elan {
struct i2chid_ops ops;
struct regulator *vcc33;
struct regulator *vccio;
struct gpio_desc *reset_gpio;
bool no_reset_on_power_off;
const struct elan_i2c_hid_chip_data *chip_data;
};
static int elan_i2c_hid_power_up(struct i2chid_ops *ops)
{
struct i2c_hid_of_elan *ihid_elan =
container_of(ops, struct i2c_hid_of_elan, ops);
int ret;
gpiod_set_value_cansleep(ihid_elan->reset_gpio, 1);
if (ihid_elan->vcc33) {
ret = regulator_enable(ihid_elan->vcc33);
if (ret)
goto err_deassert_reset;
}
ret = regulator_enable(ihid_elan->vccio);
if (ret)
goto err_disable_vcc33;
if (ihid_elan->chip_data->post_power_delay_ms)
msleep(ihid_elan->chip_data->post_power_delay_ms);
gpiod_set_value_cansleep(ihid_elan->reset_gpio, 0);
if (ihid_elan->chip_data->post_gpio_reset_on_delay_ms)
msleep(ihid_elan->chip_data->post_gpio_reset_on_delay_ms);
return 0;
err_disable_vcc33:
if (ihid_elan->vcc33)
regulator_disable(ihid_elan->vcc33);
err_deassert_reset:
if (ihid_elan->no_reset_on_power_off)
gpiod_set_value_cansleep(ihid_elan->reset_gpio, 0);
return ret;
}
static void elan_i2c_hid_power_down(struct i2chid_ops *ops)
{
struct i2c_hid_of_elan *ihid_elan =
container_of(ops, struct i2c_hid_of_elan, ops);
/*
* Do not assert reset when the hardware allows for it to remain
* deasserted regardless of the state of the (shared) power supply to
* avoid wasting power when the supply is left on.
*/
if (!ihid_elan->no_reset_on_power_off)
gpiod_set_value_cansleep(ihid_elan->reset_gpio, 1);
if (ihid_elan->chip_data->post_gpio_reset_off_delay_ms)
msleep(ihid_elan->chip_data->post_gpio_reset_off_delay_ms);
regulator_disable(ihid_elan->vccio);
if (ihid_elan->vcc33)
regulator_disable(ihid_elan->vcc33);
}
static int i2c_hid_of_elan_probe(struct i2c_client *client)
{
struct i2c_hid_of_elan *ihid_elan;
int ret;
ihid_elan = devm_kzalloc(&client->dev, sizeof(*ihid_elan), GFP_KERNEL);
if (!ihid_elan)
return -ENOMEM;
ihid_elan->ops.power_up = elan_i2c_hid_power_up;
ihid_elan->ops.power_down = elan_i2c_hid_power_down;
/* Start out with reset asserted */
ihid_elan->reset_gpio =
devm_gpiod_get_optional(&client->dev, "reset", GPIOD_OUT_HIGH);
if (IS_ERR(ihid_elan->reset_gpio))
return PTR_ERR(ihid_elan->reset_gpio);
ihid_elan->no_reset_on_power_off = of_property_read_bool(client->dev.of_node,
"no-reset-on-power-off");
ihid_elan->vccio = devm_regulator_get(&client->dev, "vccio");
if (IS_ERR(ihid_elan->vccio)) {
ret = PTR_ERR(ihid_elan->vccio);
goto err_deassert_reset;
}
ihid_elan->chip_data = device_get_match_data(&client->dev);
if (ihid_elan->chip_data->main_supply_name) {
ihid_elan->vcc33 = devm_regulator_get(&client->dev,
ihid_elan->chip_data->main_supply_name);
if (IS_ERR(ihid_elan->vcc33)) {
ret = PTR_ERR(ihid_elan->vcc33);
goto err_deassert_reset;
}
}
ret = i2c_hid_core_probe(client, &ihid_elan->ops,
ihid_elan->chip_data->hid_descriptor_address, 0);
if (ret)
goto err_deassert_reset;
return 0;
err_deassert_reset:
if (ihid_elan->no_reset_on_power_off)
gpiod_set_value_cansleep(ihid_elan->reset_gpio, 0);
return ret;
}
static const struct elan_i2c_hid_chip_data elan_ekth6915_chip_data = {
.post_power_delay_ms = 1,
.post_gpio_reset_on_delay_ms = 300,
.hid_descriptor_address = 0x0001,
.main_supply_name = "vcc33",
};
static const struct elan_i2c_hid_chip_data ilitek_ili9882t_chip_data = {
.post_power_delay_ms = 1,
.post_gpio_reset_on_delay_ms = 200,
.post_gpio_reset_off_delay_ms = 65,
.hid_descriptor_address = 0x0001,
/*
* this touchscreen is tightly integrated with the panel and assumes
* that the relevant power rails (other than the IO rail) have already
* been turned on by the panel driver because we're a panel follower.
*/
.main_supply_name = NULL,
};
static const struct elan_i2c_hid_chip_data ilitek_ili2901_chip_data = {
.post_power_delay_ms = 10,
.post_gpio_reset_on_delay_ms = 100,
.hid_descriptor_address = 0x0001,
.main_supply_name = "vcc33",
};
static const struct of_device_id elan_i2c_hid_of_match[] = {
{ .compatible = "elan,ekth6915", .data = &elan_ekth6915_chip_data },
{ .compatible = "ilitek,ili9882t", .data = &ilitek_ili9882t_chip_data },
{ .compatible = "ilitek,ili2901", .data = &ilitek_ili2901_chip_data },
{ }
};
MODULE_DEVICE_TABLE(of, elan_i2c_hid_of_match);
static struct i2c_driver elan_i2c_hid_ts_driver = {
.driver = {
.name = "i2c_hid_of_elan",
.pm = &i2c_hid_core_pm,
.probe_type = PROBE_PREFER_ASYNCHRONOUS,
.of_match_table = of_match_ptr(elan_i2c_hid_of_match),
},
.probe = i2c_hid_of_elan_probe,
.remove = i2c_hid_core_remove,
.shutdown = i2c_hid_core_shutdown,
};
module_i2c_driver(elan_i2c_hid_ts_driver);
MODULE_AUTHOR("Douglas Anderson <dianders@chromium.org>");
MODULE_DESCRIPTION("Elan i2c-hid touchscreen driver");
MODULE_LICENSE("GPL");
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